Electronic musical instrument key-operated switch assembly having vibration-absorber attached to movable contact member

ABSTRACT

In a key-operated switch assembly having a movable and a stationary contact member, a soft shock or vibration absorbing member is attached to the movable contact member. The shock absorbing member is made of elastic or resilient material having greater shock or vibration absorbing capacity and is molded into one integral piece along with an actuator actuating the movable contact member. The shock absorbing member may be provided with a thin tongue-like projection extending toward the free end of the contact member so as to obtain a better shock absorbing effect.

States Patent [191 [451 May 22,1973

ELECTRONIC MUSICAL INSTRUMENT KEY-OPERATED SWITCH ASSEMBLY HAVING VEBRATHON-ABSO i ATTACHED TO MOVABLE CONTACT MEMER Inventor: Masakatsu Iijima, Shizuaka-ken, l-lammamatsu-shi, Japan Assignee: Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu-shi, Shizvokaken, Japan Filed: Dec. 22, 1971 Appl. No.: 210,890

Foreign Application Priority Data Dec. 26, 1970 Japan ..45/131831 [1.8. Ci. ..200/166 D, 200/166 J Int. Cl. ..H0lh 1/50 Field of Search ..200/166 H, 166 J,

[56] References Cited UNITED STATES PATENTS 3,600,543 8/1971 Nakada ..200/166 H 3,248,488 4/1966 3,304,491 2/1967 3,663,776 5/1972- 3,485,982 12/1969 Maire ..200/166 J X Primary ExaminerRobert K. Schaefer Assistant Examiner-William J. Smith Attorney-Robert D. .Flynn, Stephen H. Frishauf Leonard Holtz et al.

[5 7] ABSTRACT in a key-operated switch assembly having a movable and a stationary contact member, a soft shock or vibration absorbing member is attached to the movable contact member. The shock absorbing member is made of elastic or resilient material having greater shock or vibration absorbing capacity and is molded into one integral piece along with an actuator actuating the movable contact member. The shock absorbing member may be provided with a thin tongue-like projection extending toward the free end of the contact member so as to obtain a better shock absorbing effect.

12 Claims, 4 Drawing Figures ELECTRONIC MUSICAL INSTRUMENT KEY-OPERATED SWITCH ASSEMBLY HAVING VIBRATION-ABSORBER ATTACHED TO MOVABLE CONTACT MEMBER SUMMARY OF THE INVENTION This invention relates to a key or key-operated switch assembly particularly adaptable for use in an electronic musical instrument.

As generally known, the key switch assembly comprises one or more switch units, each of which involves a stationary contract member, an elastically bendable or movable contact member, and an actuator for striking against the latter contact member, the actuator being operated by a key. For conventional electronic musical instruments, however, there must be avoided as much as possible the mechanical shock noises generated by the key striking against the actuator, and by the actuator striking the bendable contact member and by the contact between the stationary contact member and the elastically contact member.

With the conventional electronic musical instruments, it is further desired to eliminate electrical click noises generated by the contact between the movable and stationary contact members made especially when both members are brought into contact with each other with the movable contact member subjected to a continuing vibration. Since the key switch assembly generally consists of a large number of switch units, it is further desired that the assembly be of such construction as permits easy fabrication.

An object of this invention is, therefore, to provide a key-operated switch assembly so improved as to avoid the generation of mechanical and electrical noises, the assembly being of such construction as permits easy fabrication thereof.

SUMMARY OF THE INVENTION According to a first aspect of the present invention, the movable contact member of a key-operated switch assembly is provided with an integral piece of a material promoting damping of vibration, the integral piece comprising a vibration absorbing member attached to the movable contact member and a tongue-like projecting member made of the same material as that of the vibration absorbing member and provided over one side of the movable contact member. The tongue-like projecting member extends from the vibration absorbing member and is in face-to-face contact with the movable member.

According to a further aspect of the invention, the integral piece above-described further comprises an actuating member made of the same material as that of the vibration absorbing member and extending from the vibration absorbing member toward the key so as to be directly actuated by the key.

According to still a further aspect of the invention, the integral piece on the movable contact member of a key-operated switch assembly is formed of a material promoting damping of vibration, the integral piece comprising a vibration absorbing member attached to the movable contact member, and an actuating membermade of the same material as that of the vibration absorbing member and extending from the vibration absorbing member toward the key so as to be directly actuated by the key.

Further, in accordance with the present invention,

multiple movable contact switch devices are provided.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a crosssectional side view of a key switch assembly embodying the present invention;

FIG. 2 is a fragmentary perspective view of a movable contact member used for the key switch assembly, according to the invention;

FIG. 3 is a fragmentary perspective view of the movable contact member with a vibration absorbing member attached thereto; and

FIG. 4 is a side view of another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a key-operated switch assembly comprising one switch unit in corresponding relationship with each of juxtaposed key members 10 incorporated in an electronic musical instrument. Each of the key members 10 is swingably supported by causing a V- shaped groove formed at its rear portion to engage with the upper edge of a vertically extending fulcrum member 11. The latter fulcrum member 11 has a rearwardly bent lower portion, and a coiled spring 13 bridges the rear ends of the bent portion and key member.

The vertically extending fulcrum member 11 is attached to the rear end of a horizontal bed frame member 14 having its front portion stepped downward from the rearward main portion thereof, while the front end of the latter member 14 is fitted with a channel-shaped front frame member 15. The vertical swingable movement of the key member is restricted by two stop members 16 and 17 of soft material fitted to the inner wall of the upper flange of the front frame member 15 and mounted on the aforesaid downward stepped portion of the bed frame member 14, respectively.

At the lower side of the bed frame member 14 are disposed first and second supporting members 18 and 19 of electrically insulating material such as synthetic resin. To the first supporting member 18 are attached bar-shaped stationary contact members 20 and 21 of electrically conducting material extending in the transverse direction of the key member 11. An elongated leaf-shaped elastically bendable or movable contact member 22 of electrically conducting material is attached to the second supporting member 19 and forwardly extends therefrom in a manner to cause its free end portion to be disposed between both stationary contact members 20 and 21 and normally in contact with one member 20 of the stationary members under a biasing force of the movable contact member itself. The movable contact member 22 is preferably made of phospher bronze or nickel silver, having a small thickness but a substantial width with the width of the free end portion narrowing decreasingly toward its free end, as shown in FIGS. 2 and 3.

As clearly shown in FIG. 3, the movable contact member 22 has at an intermediate portion between the free end and the fixed end thereof an integrally molded piece 23 formed from elastic or resilient materials sufficiently soft to permit prominent attenuation or damp ing of vibration or shock applied thereto, such as plasticized polyvinyl chloride, neoprene rubber of isobutylene-isoprene rubber, by means of insert-molding techniques as well known in the art. The molded piece 23 essentially consists of two integral parts, one of which is a vibration or shock absorbing member 24 pene trated by the movable contact member 22 and provided with a tongue-like member 25 extending therefrom toward the free end of the movable member 22 on the upper surface thereof, the member 25 having a width substantially equal to that of the movable contact member 22 and being in direct contact therewith, and the other of which is an actuator 26 extending from the vibration absorbing member 24 upwardly in a direction substantially perpendicular to the lengthwise direction of the movable contact member 22. It is preferred that the whole area of one side of the tongue-like member 25 is in contact with the member 22. The vibration absorbing member 24, tongue-like member 25 and actuator 26 are molded from the above-mentioned material into one integral piece. The actuator or actuating member 23 is movably inserted in a hole perforated in the bed frame 14, with the upper end of the actuator confronted with an attachment 27 fixed to the bottom of the key so as to enable the actuator 23 to be moved thereby. In connection with the insert-molding of the piece 23, perforation of the movable contact member 22 with one or more apertures 28 prior to the molding operation, as shown in FIG. 2, enables the piece 23 to be fitted to the movable contact member 22 more securely, since, when being molded, the resinous material forming the piece 23 flows into the aperture or apertures 28 and engages the piece with the movable contact member through that portion of the material located in the aperture or apertures 28. Finally, numerals 29 appearing in FIG. 1 denote a bottom covering member for the switching arrangement.

In operation, the depression of the key member 11 causes the key bottom attachment 27 noiselessly to strike against the top end of the actuator 26 made of soft material and then bend the body of the movable contact member 22 until the free end portion of the latter member 22 comes in contact with the stationary contact member 21 so as to be electrically connected therewith. When the force applied to the key member is released, the key member 11 is automatically returned by the action of the coiled spring 13 and concurrently the movable contact member 22 is returned to the original position by means of its own biasing force. In such switching behavior, it will be understood that vibration or shock occurring in the movable contact member 22 upon its contact with the stationary contact members 20 or 21 can be fully and quickly absorbed or damped by the vibration absorbing member 24, and further, the tongue-like projection 25 positively promotes the absorption or damping.

According to this invention, no noise is generated by the striking of the actuator 26 against the movable contact member 22. Further, the vibration or shock caused in the movable contact member 22 is effectively absorbed by the one integral piece 23, and therefore both mechanical and electrical noises are reduced to a minimum. Furthermore, the actuator 26 is formed integrally with the vibration absorbing member 24, and this eliminates the provision of a separate actuator support ing means, making the whole switching unit compact.

FIG. 4 shows a key switch assembly of the multicontact type according to this invention wherein there are vertically arranged in spaced relationship three elastically bendable or movable contact members 22a, 22b and 220 which are respectively provided with integrally molded pieces 23a, 23b and 23c.

The molded piece 230 is formed in the shape identical with that of the piece 23 according to the abovementioned embodiment, that is, it essentially consists of a vibration absorbing member 24a, a tongue-like member 25a, and an actuating member 26a, these members 24a, 25a and 26a being integrally molded with each other. The other molded pieces 23b and 230 are shaped somewhat different from the piece 23a. Each of the pieces 23b and 23c is comprised only of a vibration absorbing member 24b or 24c and a tonguelike member 25b or 25c, and, unlike the piece 230, is not provided with any actuator. The piece 23a is superimposed on the piece 23b, and the piece 23b on the piece 230, so that the depression of the actuator 260 permits all of the movable contact members 22a, 22b and 220 to be moved downward at the same time. Similarly to the first embodiment, the pieces 23a, 23b and 230 may be fixed to the movable contact members 22a,22b, and 22c by engaging a part of each piece in the hole formed in each movable contact member. It will be apparent that this embodiment can offer-the same advantages as those of the preceding embodiment.

What is claimed is:

1. In a key-operated switch assembly having a key, a stationary contact member, and a movable contact member which is movable to and away from the stationary contact member,

the improvement wherein there is provided an integral piece of a material promoting damping of vibration, said integral piece comprising a vibration abosrbing member attached to the movable contact member, a tongue-like projecting member made of the same material as that of the vibration absorbing member and provided over one side of the movable contact member, said tongue-like projecting member extending from said vibration absorbing member and being in face-to-face contact with the movable contact member, and an actuating member made of the same material as that of the vibration absorbing member, said actuating member extending from said vibration absorbing member toward the key so as to be directly actuated by the key.

2. A key-operated switch assembly as claimed in claim 1 wherein the movable contact member is perforated with at least one hole, and said integral piece is engaged in said at least one hole.

3. A key-operated switch assembly as claimed in claim 1 wherein the movable contact member has one end fixed and the other end free, and said tongue-like member extends toward said free end of said movable contact member.

4. A key-operated switch assembly as claimed in claim 1 wherein said tongue-like projecting member is in face-to-face contact with the upper surface of said movable contact member.

5. In a key-operated switch assembly having a key, a stationary contact member, and a movable contact member which is movable to and away from the stationary contact member,

the improvement wherein there is provided an integral piece of a material promoting damping of vibration,

said integral piece comprising a vibration absorbing member attached to the movable contact member, and an actuating member made of the same material as that of the vibration absorbing member, said actuating member extending from said vibration absorbing member toward the key so as to be directly actuated by the key.

6. A key-operated switch assembly as claimed in claim 4 wherein the movable contact member is perforated with at least one hole, and said integral piece is engaged in said at least one hole.

7. in a key-operated switch assembly having a key, a stationary contact member, and a movable contact member disposed movably to and away from the stationary contact member,

the improvement wherein there is provided an integral piece of a material promoting damping of vibration,

said integral piece comprising a vibration absorbing member attached to the movable contact member, and a tongue-like projecting member made of the same material as that of the vibration absorbing member and provided over one side of the movable contact member, said tongue-like projecting member extending from said vibration absorbing member and being in face-to-face contact with the movable contact member.

8. A key-operated switch assembly as claimed in claim 7 wherein the movable contact member is perforated with at least one hole, and said integral piece is engaged in said at least one hole.

9. A key-operated switch assembly as claimed in claim 7 wherein the movable contact member has one end fixed and the other end free, and said tongue-like member extends toward said free end of said movable contact member.

10. A key-operated switch assembly as claimed in claim 7 wherein said tongue-like projecting member is in face-to-face contact with the upper surface of said movable contact member.

11. In a key-operated switch assembly having a key, a plurality of stationary contact members vertically arranged, and a plurality of movable contact members corresponding to the respective stationary contact members and being vertically spaced from each other,

the improvement comprising;

a first integral piece of a material promoting damping of vibration, said first integral piece comprising a first vibration absorbing member attached to one of the movable contact members, and a first actuating member made integral with, and of the same material as that of, the first vibration absorbing member, said first actuating member extending from said first vibration absorbing member toward the key so as to be directly acuated by the key; and

second integral pieces of a material promoting damping of vibration, each of said second integral pieces comprising a vibration absorbing member respectively attached to each of the other movable contact members, adjacent ones of said first and second integral pieces being superimposed successively on each other so that all of said movable contact members are actuated by the key.

12. A key-operated switch assembly as claimed in claim 11 wherein each of said integral pieces further comprises a tongue-like projecting member made of the same material as that of each vibration absorbing member and provided over one side of the movable contact member, said tongue-like projecting member extending from said vibration absorbing member and being in face-to-face contact with the movable contact member. 

1. In a key-operated switch assembly having a key, a stationary contact member, and a movable contact member which is movable to and away from the stationary contact member, the improvement wherein there is provided an integral piece of a material promoting damping of vibration, said integral piece comprising a vibration abosrbing member attached to the movable contact member, a tongue-like projecting member made of the same material as that of the vibration absorbing member and provided over one side of the movable contact member, said tongue-like projecting member extending from said vibration absorbing member and being in face-to-face contact with the movable contact member, and an actuating member made of the same material as that of the vibration absorbing member, said actuating member extending from said vibration absorbing member toward the key so as to be directly actuated by the key.
 2. A key-operated switch assembly as claimed in claim 1 wherein the movable contact member is perforated with at least one hole, and said integral piece is engaged in said at least one hole.
 3. A key-operated switch assembly as claimed in claim 1 wherein the movable contact member has one end fixed and the other end free, and said tongue-like member extends toward said free end of said movable contact member.
 4. A key-operated switch assembly as claimed in claim 1 wherein said tongue-like projecting member is in face-to-face contact with the upper surface of said movable contact member.
 5. In a key-operated switch assembly having a key, a stationary contact member, and a movable contact member which is movable to and away from the stationary contact member, the improvement wherein there is provided an integral piece of a material promoting damping of vibration, said integral piece comprising a vibration absorbing member attached to the movable contact member, and an actuating member made of the same material as that of the vibration absorbing member, said actuating member extending from said vibration absorbing member toward the key so as to be directly actuated by the key.
 6. A key-operated switch assembly as claimed in claim 4 wherein the movable contact member is perforated with at least one hole, and said integral piece is engaged in said at least one hole.
 7. In a key-operated switch assembly having a key, a stationary contact member, and a movable contact member disposed movably to and away from the stationary contact member, the improvement wherein there is provided an integral piece of a material promoting damping of vibration, said integral piece comprising a vibration absorbing member attached to the movable contact member, and a tongue-like projecting member made of the same material as that of the vibration absorbing member and provided over one side of the movable contact member, said tongue-like projecting member extending from said vibration absorbing member and being in face-to-face contact with the movable contact member.
 8. A key-operated switch assembly as claimed in claim 7 wherein the movable contact member is perforated with at least one hole, and said integral piece is engaged in said at least one hole.
 9. A key-operated switch assembly as claimed in claim 7 wherein the movable contact member has one end fixed and the other end free, and said tongue-like member extends toward said free end of said movable contact member.
 10. A key-operated switch assembly as claimed in claim 7 wherein said tongue-like projecting member is in face-to-face contact with the upper surface of said movable contact member.
 11. In a key-operated switch assembly having a key, a plurality of stationary contact members vertically arranged, and a plurality of movable contact members corresponding to the respective stationary contact members and being vertically spaced from each other, the improvement comprising; a first integral piece of a material promoting damping of vibration, said first integral piece comprising a first vibration absorbing member attached to one of the movable contact members, and a first actuating member made integral with, and of the same material as that of, the first vibration absorbing member, said first actuating member extending from said first vibration absorbing member toward the key so as to be directly acuated by the key; and second integral pieces of a material promoting damping of vibration, each of said second integral pieces comprising a vibration absorbing member respectively attached to each of the other movable contact members, adjacent ones of said first and second integral pieces being superimposed successively on each other so that all of said movable contact members are actuated by the key.
 12. A key-operated switch assembly as claimed in claim 11 wherein each of said integral pieces further comprises a tongue-like projecting member made of the same material as that of each vibration absorbing member and provided over one side of the movable contact member, said tongue-like projecting member extending from said vibration absorbing member and being in face-to-face contact with the movable contact member. 